Communications: electrical – Continuously variable indicating – With meter reading
Patent
1993-10-15
1996-10-29
Bowler, Alyssa H.
Communications: electrical
Continuously variable indicating
With meter reading
340572, H04L 7033, H04Q 904, G08B 706
Patent
active
055700861
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to fixed facilities that carry out two-way communication of data in a noncontacting manner with respect chiefly to power sourceless data carriers which are distant by more than several centimeters, the distance being always subject to change. Particularly, the invention relates to a countermeasure for preventing interference among the fixed facilities that can develop when a plurality of fixed facilities are arranged within a short distance from each other and when the individual fixed facilities communicate with the data carriers.
BACKGROUND ART
A variety of systems using data carrier of the electromagnetically coupled type have heretofore been proposed depending upon the communication systems and the power source systems. First, the power source systems can be divided into those of the cell-containing type in which the data carrier contains a cell and the power sourceless type which does not contain the cell but which receives an electromagnetic signal transmitted from the fixed facility and rectifies the signal to obtain a voltage that serves as a power source. The communication systems can be divided into those of the one-way communication type in which the data stored in the data carrier are transmitted to the fixed facility and those of the two-way communication type in which the data stored in the data carrier can be rewritten depending upon the data transmitted from the fixed facility; and the data can also be transmitted from the data carrier to the fixed facility. Moreover, the two-way communication systems can be classified into those of the two-frequency type in which a frequency of an AC magnetic field generated by the fixed facility is different from a frequency of an AC magnetic field generated by the data carrier and those of the one-frequency type which use the same frequency. The present invention is chiefly concerned with a power sourceless two-way communication system which uses only one frequency.
Described below are conventional examples of each of the above-mentioned systems. First, the two-way communication systems to which the present invention is concerned have been disclosed in Japanese Unexamined Patent Publications (Kokai) Nos. 2-291091, 3-273465 and 4-692. There have further been proposed power sourceless two-way communication systems that resemble the present invention, and Japanese Examined Patent Publication (Kokoku) No. 3-12353 discloses the one which is of the two-frequency type. Moreover, those of the power sourceless one-way communication type have been disclosed in Japanese Examined Patent Publications (Kokoku) Nos. 3-19591, 3-12352, U.S. Pat. Nos. 3,964,024 and 4,129,855. In particular, Japanese Examined Patent Publication (Kokoku) No. 3-25832 discloses a communication system of the power sourceless one-frequency one-way type to which the present invention is related. However, all of the above-mentioned prior art documents employ only one fixed facility and one data carrier, and do not give any attention concerning the problem of interference among fixed facilities that develops when the individual fixed facilities communicate simultaneously with the data carriers.
The problem of interference among the fixed facilities which will be considered below is the principal object of the present invention over the aforementioned prior art. First, Japanese Unexamined Patent Publications (Kokai) Nos. 2-291091, 3-273465 and 4-692 simply disclose the idea of two-way communication systems but do not at all concretely disclose the communication systems. On account of their cell-containing system, however, it is considered that these prior art disclosures must employ the two-frequency system. Japanese Examined Patent Publication (Kokoku) No. 3-12353 employs the two-frequency system as described above. In the case of the two-frequency system, the problem of interference among the fixed facilities can be avoided by separating the two kinds of frequencies using different filters, as is well known.
In the case of the one-way communicatio
REFERENCES:
patent: 3964024 (1976-06-01), Hutton et al.
patent: 3969732 (1976-07-01), Holloway
patent: 4129855 (1978-12-01), Rodrian
patent: 4857893 (1989-08-01), Carroll
patent: 5028918 (1991-07-01), Giles et al.
patent: 5061941 (1991-10-01), Lizzi et al.
patent: 5221831 (1993-06-01), Geiszler
patent: 5235326 (1993-08-01), Beigel et al.
patent: 5337040 (1994-08-01), Kind
patent: 5349339 (1994-09-01), Kind
Hanaoka Tadashi
Higuchi Haruhiko
Bowler Alyssa H.
Citizen Watch Co. Ltd.
Rinehart Mark H.
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